Automotive ignition contact points



Nov. 1, 1955 F. SKAY 2,722,584

AUTOMOTIVE IGNITION CONTACT POINTS Filed July 12, 1952 Frank Shay IN VEN TOR.

BY M4 477O4/VEY Patented Nov. 1, 1955 AUTOMOTIVE IGNITION CONTACT POINTSFrank Skay, Detroit, Mich, assiguor to Holley Carburetor Company,Detroit, Mich., a corporation of Michigan Application July 12, 1952,Serial NO. 298,496

3 Claims. (Cl. 200-166) The object of this invention is to prolong thelife of the contact points of a pair of ordinary tungsten contact pointson the low tension side of an automotive ignition system.

The characteristic failure of such points is caused by the transfer ofmetal from the plus to the minus side, which produces the well knownpyramid effect and thus shortens the life of the pair of contact points.By distributing the build up around a pre-formed crater in the positivecontact, I have gained an improved life.

Figure 1 shows the preferred form of my invention.

Figure 2 shows a cross-sectional elevation on plane 22 of Figure 1.

Figure 3 shows an alternative construction.

Figure 4 shows an enlarged cross section elevation corresponding toFigure 2.

Figure 5 shows the transfer of metal with construction shown in Figure3.

Figure 6 shows the transfer of metal with construction shown in Figure2.

In the figures:

A is the moving positive tungsten point having a cavity K mounted on anarm E.

B is the stationary negative tungsten point without any cavity mountedon an upright C of a bracket N.

D is the insulated rubbing block which engages with a cam (not shown)and causes the arm E to move and the contacts A and B to open and shut.

F is the spring which forces the rubbing block D into engagement withthe cam (not shown). F is also a conductor leading current fromelectrical connection M. The stationary contact B and the arm C are allintegral with the entire bracket N adjustably mounted on plate S.

R and O are two slots in N to permit the bracket N to be adjusted aroundits insulated pivot Q which locates on the plate S.

The Figures 3 and 4 show a stationary positive contact H with cavity Lmounted on bracket C of entire bracket N. i

I is the negative contact mounted on the breaker arm E.

Figure 5 shows the direction of transfer of the metal when the contact H(stationary) is positive.

Figure 6 shows the direction of transfer of the metal when the movingcontact A is positive.

Operation 1. The movement of the arm forces air into the cavity,cushioning the impact of the two contacts; and

2. At the same time provides cooling.

3. Tungsten metal transfer from the cavity side prevents any confinedcentral interference such as a high area within a cavity.

4. Pressure created in the center of the contacts when closed reducesarcing when they break.

What I claim is:

1. A pair of positive and negative contacts for an ignition system foran internal combustion engine comprising a stationary contact point anda moving contact point, one point being plus and the other point beingminus, a preformed cavity in the positive contact point the cavity beingso formed that it traps air in and expels air from the cavity at themoment of making contact and provides a substantial area of contact, theother contact point being flat and both being unperforated.

2. A combination of contacts as set forth in claim 1 in which thepositive contact having the cavity is the moving contact of the pair.

3. A combination of contacts as set forth in claim 1 in which thepositive contact having the cavity is the stationary contact of thepair.

References Cited in the file of this patent UNITED STATES PATENTS1,653,823 Pudelko Dec. 27, 1927 2,072,112 King Mar. 2, 1937 2,339,996Kight Jan. 25, 1944 2,634,341 Rosen Apr. 7, 1953

